The present invention relates to a loading head for pressing explosive containers and in particular to heads having an annular switching device mounted within a cavity.
In the past a group of explosive grenades have been fitted into a projectile by means of a press. Typically, the grenades are positioned at grenade receptacles in the projectile and are forced thereinto by a placing member having a pattern of cavities matching that of the grenade receptacles. The placing member is driven by a conventional hydraulic ram or other pressing machine. During this operation the safety pin in the grenade is automatically removed. Normally such removal does not arm the grenade and complete the path of the explosive train. The path is completed when a safety slider in the grenade springs to its fully extended position, thereby inserting a detonator into the explosive train. The slider is normally retained in its retracted position by the fuze mechanism until the projectile and its grenades are launched.
However, the fuze mechanism may be defective so that when a safety pin is removed the slide travels until it is stopped by contacting a restraining surface or, if there is no such restraint, until it reaches the fully armed position. The placing member has a cavity shaped and sized to restrict the movement of the slider; so configured, the safety slider is restrained from reaching the armed position while the placing member engages it even though the other safeties fail to function.
When the placing head has seated the grenades and withdrawn the safety pins as described, the hydraulic or other pressing machine automatically withdraws, leaving the grenades partially captive in the projectile. When the bottom of the placing head clears the level of the slide during this withdrawal action, a fuze whose slider has been released by a defective safety and retained by the cavity wall up to this point will extend to the fully armed position. With the slider thus extended, the grenade is likely to explode. In the past a press operator was required to observe whether the safety slider extended into its armed position after the safety pin was removed and the placing member was removed. This approach, relying on the diligence and care of the press operator, is necessarily subject to the disastrous consequences of human errors and ommissions. In the event that a single grenade explodes, all of the others are likely to explode simultaneously.
The present invention reduces such problems and dangers by adding to each cavity an annular switching device which encircles the slider when the grenade is engaged. The annular switch can be actuated in the event that the slider improperly extends while the grenade is being engaged by the placing member. Actuation of the annular switch can be used to stop the movement of the ram that is pressing the placing member.
If the placing member is thus retained in engagement with the grenade, the danger of inadvertent explosion is substantially reduced. In the preferred embodiment, the cavity of the placing member surrounding the slider is sufficiently small that the slider cannot fully extend. Accordingly, the grenade is maintained in a disarmed position so that the operator can take steps to safely disarm the defective grenade. Therefore, apparatus according to the present invention significantly improves safety and efficiency in the manufacture of weapons.